Satterlie, Richard A. (2011). "Do jellyfish have central nervous systems?". Journal of Experimental Biology. 214 (8): 1215–1223. doi: 10.1242/jeb.043687. PMID 21430196. Jellyfish are truly fascinating creatures that manage to survive without many of the organs we now consider vital, and their bodies are well suited to survive the conditions of the endless blue, drifting across the vast oceans, displaying their beauty for all to see—at a safe distance! The study of jellyfish eye evolution is an intermediary to a better understanding of how visual systems evolved on Earth. [40] Jellyfish exhibit immense variation in visual systems ranging from photoreceptive cell patches seen in simple photoreceptive systems to more derived complex eyes seen in box jellyfish. [40] Major topics of jellyfish visual system research (with an emphasis on box jellyfish) include: the evolution of jellyfish vision from simple to complex visual systems), the eye morphology and molecular structures of box jellyfish (including comparisons to vertebrate eyes), and various uses of vision including task-guided behaviors and niche specialization. a b c d e f Nilsson, DE (2013). "Eye evolution and its functional basis". Visual Neuroscience. 30 (1–2): 5–20. doi: 10.1017/S0952523813000035. PMC 3632888. PMID 23578808. Jellyfish have a complex life cycle which includes both sexual and asexual phases, with the medusa being the sexual stage in most instances. Sperm fertilize eggs, which develop into larval planulae, become polyps, bud into ephyrae and then transform into adult medusae. In some species certain stages may be skipped. [65]

A free-swimming marine coelenterate that is the sexually reproducing form of a hydrozoan or scyphozoan and has a nearly transparent saucer-shaped body and extensible marginal tentacles studded with stinging cells. [15]In one set of experiments, the researchers dissected Caribbean box jellyfish to isolate the rhopalia. Kier, William (2012). "The diversity of hydrostatic skeletons". Journal of Experimental Biology. 215 (Pt 8): 1247–1257. doi: 10.1242/jeb.056549. PMID 22442361. With a new genetic toolbox, researchers can view jellyfish neurons as they light up in real time. Jellyfish do not have a centralized brain; rather, their brain cells (neurons) are distributed in a diffuse net throughout the body. As shown in this video, this study discovered that there is actually spatial organization to the way that neurons are activated when the animal is coordinating behavior. Credit: B. Weissbourd Now researchers studying the tiny Caribbean box jellyfish say they have found these creatures are able to learn from past experiences in a process called associative learning, just as Pavlov’s dogs learned to salivate at the sound of a bell. By examining the glowing chain reactions occurring in the animals' neurons as they ate, the team determined that a subnetwork of neurons that produces a particular neuropeptide (a molecule produced by neurons) is responsible for the spatially localized inward folding of the body. Additionally, though the network of jellyfish neurons originally seemed diffuse and unstructured, the researchers found a surprising degree of organization that only became visible with their fluorescent system.

The paper is titled "A genetically tractable jellyfish model for systems and evolutionary neuroscience." Traditional processing methods, carried out by a jellyfish master, involve a 20- to 40-day multi-phase procedure in which, after removing the gonads and mucous membranes, the umbrella and oral arms are treated with a mixture of table salt and alum, and compressed. Processing makes the jellyfish drier and more acidic, producing a crisp texture. Jellyfish prepared this way retain 7–10% of their original weight, and the processed product consists of approximately 94% water and 6% protein. Freshly processed jellyfish has a white, creamy color and turns yellow or brown during prolonged storage. [126] Klappenbach, Laura. "Ten Facts about Jellyfish". Archived from the original on 26 February 2009 . Retrieved 24 January 2010. They are quite unintelligent compared to other fish and animals in the sea. They do not have complicated organs. They just have a basic set of nerves in their body. Hence they do not exhibit any advanced behavior. They do not have the ability to think, store and process information. Unlike other animals which use their brain to function efficiently, the jellyfish is focused and built for survival. These basic sets of nerves are more than enough to help them perform day to day activities for survival. But some people have a different opinion. They think that jellyfish are actually doing quite well for an animal with no brain. Whether a jellyfish is intelligent or not actually depends on how you look at it. Vinegar (3–10% aqueous acetic acid) may help with box jellyfish stings [148] [149] but not the stings of the Portuguese man o' war. [148] Clearing the area of jelly and tentacles reduces nematocyst firing. [150] Scraping the affected skin, such as with the edge of a credit card, may remove remaining nematocysts. [151] Once the skin has been cleaned of nematocysts, hydrocortisone cream applied locally reduces pain and inflammation. [152] Antihistamines may help to control itching. [151] Immunobased antivenins are used for serious box jellyfish stings. [153] [154]

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The darker red colored brain used 2 boxes of peach and one strawberry. Much darker in color, and still creepy, but defiantly not as fleshy looking. Most animals have some sort of centralized nerve center, aka a brain, although many have only simple versions called ganglia – concentrations of nerves that control other nerves around them. Jellyfish have no such central place; in fact, they have two nervous systems. A large nerve net controls swimming and a small nerve net controls all other behaviors, including feeding and spasm response (briefly curling into a ball). This body-wide network of small nerves somehow makes it possible for a jelly to figure out where the different parts of its body are and to act accordingly – for example, using a single tentacle to move prey to its mouth.